Democrats pounced on special counsel Robert S. Mueller III’s indictment of a dozen Russian military officers for their efforts to interfere in the 2016 U.S. election, with some saying Monday’s Donald Trump-Vladimir Putin summit should be canceled.

“These indictments are further proof of what everyone but the president seems to understand: President Putin is an adversary who interfered in our elections to help President Trump win,” Senate Minority Leader Charles E. Schumer said in a statement.

“President Trump should cancel his meeting with Vladimir Putin until Russia takes demonstrable and transparent steps to prove that they won’t interfere in future elections,” the New York Democrat said. “Glad-handing with Vladimir Putin on the heels of these indictments would be an insult to our democracy.”

Eighteen Democratic members of the House Foreign Affairs Committee quickly sent Trump a letter demanding the same following the indictment announcement.

“Russia has shown itself to be an adversary of the United States and our allies and a serious threat to global peace, security, and stability,” they wrote to Trump. “And, today, Special Counsel Mueller indicted twelve Russian military officers for hacking the Democratic National Committee — a direct attack on our democracy.”

“I will absolutely bring that up. I don’t think you’ll have any, ‘Gee, I didn’t, I didn’t, you got me,’” he told reporters. “I don’t think you’ll have any Perry Mason here. I don’t think. But you never know what happens. But I’ll very firmly ask the question.”

House Minority Leader Nancy Pelosi, D-Calif., at first did not call for the Helsinki summit to be nixed, saying in a statement she wanted Trump to “demand and secure a real, concrete and comprehensive agreement that the Russians will cease their ongoing attacks on our democracy.”

But less than three hours later, the California Democrat joined the chorus of party members calling for the meeting to be canceled.

“President Trump’s continued refusal to condemn the Russians’ attacks on our democracy, even after Special Counsel Mueller indicted 12 Russian intelligence officials for interfering in the 2016 election, makes it clear that meeting with Putin would be both pointless and dangerous,” Pelosi said.

Rep. Debbie Wasserman Schultz of Florida, who was Democratic National Committee chairwoman at the time of the hacking, issued a statement Friday that said the organization “was the first major target of the Russian attack on our democracy.”

“I strongly believe that every individual who helped carry it out — foreign or domestic — should be held accountable to the fullest extent of the law,” she said. “I’m pleased that the Justice Department is following the facts wherever they may lead, despite Donald Trump’s dangerous distortions and his refusal to acknowledge the conclusions reached by the American intelligence community.”

The White House quickly tried to use the indictment to further its claims that the president’s 2016 campaign did not conspire with Russians.

“Today’s charges include no allegations of knowing involvement by anyone on the [Trump] campaign and no allegations that the alleged hacking affected the election result,” White House deputy press secretary Lindsay Walters said. “This is consistent with what we have been saying all along.”